| 浙江地开石粘土矿床热液蚀变的地球化学研究 |
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| 引用本文：.1991.Geochemical Study On Hydrothermal Alterations Of Dickite Deposits In Zhejiang Province[J].Mineral Deposits,10(4):342~348 |
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| 中文摘要:本文根据浙江一些典型地开石粘土矿床的化学成分和氢、氧同位素组成等资料，探讨了热液蚀变体系的地球化学特征及其演化过程。着重指出热液流体为来源为中生代大气降水，并在300℃较高温度下与周围岩石发生了同位素交换的循环地热水；然后，在250-100℃的中低温阶段，由该交换后的热液流体蚀变交代酸性火山岩而形成地开石粘土。 |
| 中文关键词:粘土矿床 地开石 热液体系 地球化学 浙江 |
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| Geochemical Study On Hydrothermal Alterations Of Dickite Deposits In Zhejiang Province |
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| Abstract:Based on chemical Composition and hydrogen and oxygen isotopic data of dickite deposits in Zhejiang Province, this paper discusses geochemical characteristics and evolutionary process of their hydrothermal alteration system. CIA calculations and SiO2/TiO2-A12O3/TiO2 diagrams reveal the existence of regular variation in major ore-forming chemical composition from host rock through altered rock to dickite, suggesting that dickite was formed by intense hydrothermal alteration of acid volcanic rocks. From the variation curves of isotopic composition for isotope exchange eqilibrium water between water and wall rock as well as its equilibrium mineral, it is known that hydrothermal fluids for alteration came from Mesozoic meteoric water, that cyclic geothermal water underwent isotopic exchange at higher temperature of 300℃, and dickite was formed through alteration by such cyclic geothermal water at mesothermal-epithermal stage of 250-100℃. From these data combined with ore deposit geology and alteration zoning, this paper makes a brief description of the hydrothermally evolutionary process from the pyritization-alunitization--pyrophyllitization system in an acid-slightly reducing environment through dickite (kaolinite) clayization to sericitization and silicification in a weakly acid-oxidizing environment。 |
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